docs/cut
view code/cut.c__gnu.2015-05-01 @ 16:4d8196c836d8
Referenzen eingefuegt; Todos geprueft
| author | markus schnalke <meillo@marmaro.de> |
|---|---|
| date | Tue, 12 May 2015 22:49:21 +0200 |
| parents | |
| children |
line source
1 /* cut - remove parts of lines of files
2 Copyright (C) 1997-2015 Free Software Foundation, Inc.
3 Copyright (C) 1984 David M. Ihnat
5 This program is free software: you can redistribute it and/or modify
6 it under the terms of the GNU General Public License as published by
7 the Free Software Foundation, either version 3 of the License, or
8 (at your option) any later version.
10 This program is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 GNU General Public License for more details.
15 You should have received a copy of the GNU General Public License
16 along with this program. If not, see <http://www.gnu.org/licenses/>. */
18 /* Written by David Ihnat. */
20 /* POSIX changes, bug fixes, long-named options, and cleanup
21 by David MacKenzie <djm@gnu.ai.mit.edu>.
23 Rewrite cut_fields and cut_bytes -- Jim Meyering. */
25 #include <config.h>
27 #include <stdio.h>
28 #include <assert.h>
29 #include <getopt.h>
30 #include <sys/types.h>
31 #include "system.h"
33 #include "error.h"
34 #include "fadvise.h"
35 #include "getndelim2.h"
36 #include "hash.h"
37 #include "quote.h"
38 #include "xstrndup.h"
40 /* The official name of this program (e.g., no 'g' prefix). */
41 #define PROGRAM_NAME "cut"
43 #define AUTHORS \
44 proper_name ("David M. Ihnat"), \
45 proper_name ("David MacKenzie"), \
46 proper_name ("Jim Meyering")
48 #define FATAL_ERROR(Message) \
49 do \
50 { \
51 error (0, 0, (Message)); \
52 usage (EXIT_FAILURE); \
53 } \
54 while (0)
57 struct range_pair
58 {
59 size_t lo;
60 size_t hi;
61 };
63 /* Array of `struct range_pair' holding all the finite ranges. */
64 static struct range_pair *rp;
66 /* Pointer inside RP. When checking if a byte or field is selected
67 by a finite range, we check if it is between CURRENT_RP.LO
68 and CURRENT_RP.HI. If the byte or field index is greater than
69 CURRENT_RP.HI then we make CURRENT_RP to point to the next range pair. */
70 static struct range_pair *current_rp;
72 /* Number of finite ranges specified by the user. */
73 static size_t n_rp;
75 /* Number of `struct range_pair's allocated. */
76 static size_t n_rp_allocated;
79 /* Append LOW, HIGH to the list RP of range pairs, allocating additional
80 space if necessary. Update global variable N_RP. When allocating,
81 update global variable N_RP_ALLOCATED. */
83 static void
84 add_range_pair (size_t lo, size_t hi)
85 {
86 if (n_rp == n_rp_allocated)
87 rp = X2NREALLOC (rp, &n_rp_allocated);
88 rp[n_rp].lo = lo;
89 rp[n_rp].hi = hi;
90 ++n_rp;
91 }
93 /* This buffer is used to support the semantics of the -s option
94 (or lack of same) when the specified field list includes (does
95 not include) the first field. In both of those cases, the entire
96 first field must be read into this buffer to determine whether it
97 is followed by a delimiter or a newline before any of it may be
98 output. Otherwise, cut_fields can do the job without using this
99 buffer. */
100 static char *field_1_buffer;
102 /* The number of bytes allocated for FIELD_1_BUFFER. */
103 static size_t field_1_bufsize;
105 enum operating_mode
106 {
107 undefined_mode,
109 /* Output characters that are in the given bytes. */
110 byte_mode,
112 /* Output the given delimiter-separated fields. */
113 field_mode
114 };
116 static enum operating_mode operating_mode;
118 /* If true do not output lines containing no delimiter characters.
119 Otherwise, all such lines are printed. This option is valid only
120 with field mode. */
121 static bool suppress_non_delimited;
123 /* If true, print all bytes, characters, or fields _except_
124 those that were specified. */
125 static bool complement;
127 /* The delimiter character for field mode. */
128 static unsigned char delim;
130 /* True if the --output-delimiter=STRING option was specified. */
131 static bool output_delimiter_specified;
133 /* The length of output_delimiter_string. */
134 static size_t output_delimiter_length;
136 /* The output field separator string. Defaults to the 1-character
137 string consisting of the input delimiter. */
138 static char *output_delimiter_string;
140 /* True if we have ever read standard input. */
141 static bool have_read_stdin;
143 /* For long options that have no equivalent short option, use a
144 non-character as a pseudo short option, starting with CHAR_MAX + 1. */
145 enum
146 {
147 OUTPUT_DELIMITER_OPTION = CHAR_MAX + 1,
148 COMPLEMENT_OPTION
149 };
151 static struct option const longopts[] =
152 {
153 {"bytes", required_argument, NULL, 'b'},
154 {"characters", required_argument, NULL, 'c'},
155 {"fields", required_argument, NULL, 'f'},
156 {"delimiter", required_argument, NULL, 'd'},
157 {"only-delimited", no_argument, NULL, 's'},
158 {"output-delimiter", required_argument, NULL, OUTPUT_DELIMITER_OPTION},
159 {"complement", no_argument, NULL, COMPLEMENT_OPTION},
160 {GETOPT_HELP_OPTION_DECL},
161 {GETOPT_VERSION_OPTION_DECL},
162 {NULL, 0, NULL, 0}
163 };
165 void
166 usage (int status)
167 {
168 if (status != EXIT_SUCCESS)
169 emit_try_help ();
170 else
171 {
172 printf (_("\
173 Usage: %s OPTION... [FILE]...\n\
174 "),
175 program_name);
176 fputs (_("\
177 Print selected parts of lines from each FILE to standard output.\n\
178 "), stdout);
180 emit_stdin_note ();
181 emit_mandatory_arg_note ();
183 fputs (_("\
184 -b, --bytes=LIST select only these bytes\n\
185 -c, --characters=LIST select only these characters\n\
186 -d, --delimiter=DELIM use DELIM instead of TAB for field delimiter\n\
187 "), stdout);
188 fputs (_("\
189 -f, --fields=LIST select only these fields; also print any line\n\
190 that contains no delimiter character, unless\n\
191 the -s option is specified\n\
192 -n (ignored)\n\
193 "), stdout);
194 fputs (_("\
195 --complement complement the set of selected bytes, characters\n\
196 or fields\n\
197 "), stdout);
198 fputs (_("\
199 -s, --only-delimited do not print lines not containing delimiters\n\
200 --output-delimiter=STRING use STRING as the output delimiter\n\
201 the default is to use the input delimiter\n\
202 "), stdout);
203 fputs (HELP_OPTION_DESCRIPTION, stdout);
204 fputs (VERSION_OPTION_DESCRIPTION, stdout);
205 fputs (_("\
206 \n\
207 Use one, and only one of -b, -c or -f. Each LIST is made up of one\n\
208 range, or many ranges separated by commas. Selected input is written\n\
209 in the same order that it is read, and is written exactly once.\n\
210 "), stdout);
211 fputs (_("\
212 Each range is one of:\n\
213 \n\
214 N N'th byte, character or field, counted from 1\n\
215 N- from N'th byte, character or field, to end of line\n\
216 N-M from N'th to M'th (included) byte, character or field\n\
217 -M from first to M'th (included) byte, character or field\n\
218 "), stdout);
219 emit_ancillary_info (PROGRAM_NAME);
220 }
221 exit (status);
222 }
224 /* Comparison function for qsort to order the list of
225 struct range_pairs. */
226 static int
227 compare_ranges (const void *a, const void *b)
228 {
229 int a_start = ((const struct range_pair *) a)->lo;
230 int b_start = ((const struct range_pair *) b)->lo;
231 return a_start < b_start ? -1 : a_start > b_start;
232 }
234 /* Reallocate Range Pair entries, with corresponding
235 entries outside the range of each specified entry. */
237 static void
238 complement_rp (void)
239 {
240 if (complement)
241 {
242 struct range_pair *c = rp;
243 size_t n = n_rp;
244 size_t i;
246 rp = NULL;
247 n_rp = 0;
248 n_rp_allocated = 0;
250 if (c[0].lo > 1)
251 add_range_pair (1, c[0].lo - 1);
253 for (i = 1; i < n; ++i)
254 {
255 if (c[i-1].hi + 1 == c[i].lo)
256 continue;
258 add_range_pair (c[i-1].hi + 1, c[i].lo - 1);
259 }
261 if (c[n-1].hi < SIZE_MAX)
262 add_range_pair (c[n-1].hi + 1, SIZE_MAX);
264 free (c);
265 }
266 }
268 /* Given the list of field or byte range specifications FIELDSTR,
269 allocate and initialize the RP array. FIELDSTR should
270 be composed of one or more numbers or ranges of numbers, separated
271 by blanks or commas. Incomplete ranges may be given: '-m' means '1-m';
272 'n-' means 'n' through end of line.
273 Return true if FIELDSTR contains at least one field specification,
274 false otherwise. */
276 static bool
277 set_fields (const char *fieldstr)
278 {
279 size_t initial = 1; /* Value of first number in a range. */
280 size_t value = 0; /* If nonzero, a number being accumulated. */
281 bool lhs_specified = false;
282 bool rhs_specified = false;
283 bool dash_found = false; /* True if a '-' is found in this field. */
284 bool field_found = false; /* True if at least one field spec
285 has been processed. */
287 size_t i;
288 bool in_digits = false;
290 /* Collect and store in RP the range end points. */
292 while (true)
293 {
294 if (*fieldstr == '-')
295 {
296 in_digits = false;
297 /* Starting a range. */
298 if (dash_found)
299 FATAL_ERROR (_("invalid byte, character or field list"));
300 dash_found = true;
301 fieldstr++;
303 if (lhs_specified && !value)
304 FATAL_ERROR (_("fields and positions are numbered from 1"));
306 initial = (lhs_specified ? value : 1);
307 value = 0;
308 }
309 else if (*fieldstr == ','
310 || isblank (to_uchar (*fieldstr)) || *fieldstr == '\0')
311 {
312 in_digits = false;
313 /* Ending the string, or this field/byte sublist. */
314 if (dash_found)
315 {
316 dash_found = false;
318 if (!lhs_specified && !rhs_specified)
319 FATAL_ERROR (_("invalid range with no endpoint: -"));
321 /* A range. Possibilities: -n, m-n, n-.
322 In any case, 'initial' contains the start of the range. */
323 if (!rhs_specified)
324 {
325 /* 'n-'. From 'initial' to end of line. */
326 add_range_pair (initial, SIZE_MAX);
327 field_found = true;
328 }
329 else
330 {
331 /* 'm-n' or '-n' (1-n). */
332 if (value < initial)
333 FATAL_ERROR (_("invalid decreasing range"));
335 add_range_pair (initial, value);
336 field_found = true;
337 }
338 value = 0;
339 }
340 else
341 {
342 /* A simple field number, not a range. */
343 if (value == 0)
344 FATAL_ERROR (_("fields and positions are numbered from 1"));
345 add_range_pair (value, value);
346 value = 0;
347 field_found = true;
348 }
350 if (*fieldstr == '\0')
351 break;
353 fieldstr++;
354 lhs_specified = false;
355 rhs_specified = false;
356 }
357 else if (ISDIGIT (*fieldstr))
358 {
359 /* Record beginning of digit string, in case we have to
360 complain about it. */
361 static char const *num_start;
362 if (!in_digits || !num_start)
363 num_start = fieldstr;
364 in_digits = true;
366 if (dash_found)
367 rhs_specified = 1;
368 else
369 lhs_specified = 1;
371 /* Detect overflow. */
372 if (!DECIMAL_DIGIT_ACCUMULATE (value, *fieldstr - '0', size_t)
373 || value == SIZE_MAX)
374 {
375 /* In case the user specified -c$(echo 2^64|bc),22,
376 complain only about the first number. */
377 /* Determine the length of the offending number. */
378 size_t len = strspn (num_start, "0123456789");
379 char *bad_num = xstrndup (num_start, len);
380 if (operating_mode == byte_mode)
381 error (0, 0,
382 _("byte offset %s is too large"), quote (bad_num));
383 else
384 error (0, 0,
385 _("field number %s is too large"), quote (bad_num));
386 free (bad_num);
387 exit (EXIT_FAILURE);
388 }
390 fieldstr++;
391 }
392 else
393 FATAL_ERROR (_("invalid byte, character or field list"));
394 }
396 qsort (rp, n_rp, sizeof (rp[0]), compare_ranges);
398 /* Merge range pairs (e.g. `2-5,3-4' becomes `2-5'). */
399 for (i = 0; i < n_rp; ++i)
400 {
401 for (size_t j = i + 1; j < n_rp; ++j)
402 {
403 if (rp[j].lo <= rp[i].hi)
404 {
405 rp[i].hi = MAX (rp[j].hi, rp[i].hi);
406 memmove (rp + j, rp + j + 1, (n_rp - j - 1) * sizeof *rp);
407 n_rp--;
408 j--;
409 }
410 else
411 break;
412 }
413 }
415 complement_rp ();
417 /* After merging, reallocate RP so we release memory to the system.
418 Also add a sentinel at the end of RP, to avoid out of bounds access
419 and for performance reasons. */
420 ++n_rp;
421 rp = xrealloc (rp, n_rp * sizeof (struct range_pair));
422 rp[n_rp - 1].lo = rp[n_rp - 1].hi = SIZE_MAX;
424 return field_found;
425 }
427 /* Increment *ITEM_IDX (i.e., a field or byte index),
428 and if required CURRENT_RP. */
430 static inline void
431 next_item (size_t *item_idx)
432 {
433 (*item_idx)++;
434 if ((*item_idx) > current_rp->hi)
435 current_rp++;
436 }
438 /* Return nonzero if the K'th field or byte is printable. */
440 static inline bool
441 print_kth (size_t k)
442 {
443 return current_rp->lo <= k;
444 }
446 /* Return nonzero if K'th byte is the beginning of a range. */
448 static inline bool
449 is_range_start_index (size_t k)
450 {
451 return k == current_rp->lo;
452 }
454 /* Read from stream STREAM, printing to standard output any selected bytes. */
456 static void
457 cut_bytes (FILE *stream)
458 {
459 size_t byte_idx; /* Number of bytes in the line so far. */
460 /* Whether to begin printing delimiters between ranges for the current line.
461 Set after we've begun printing data corresponding to the first range. */
462 bool print_delimiter;
464 byte_idx = 0;
465 print_delimiter = false;
466 current_rp = rp;
467 while (true)
468 {
469 int c; /* Each character from the file. */
471 c = getc (stream);
473 if (c == '\n')
474 {
475 putchar ('\n');
476 byte_idx = 0;
477 print_delimiter = false;
478 current_rp = rp;
479 }
480 else if (c == EOF)
481 {
482 if (byte_idx > 0)
483 putchar ('\n');
484 break;
485 }
486 else
487 {
488 next_item (&byte_idx);
489 if (print_kth (byte_idx))
490 {
491 if (output_delimiter_specified)
492 {
493 if (print_delimiter && is_range_start_index (byte_idx))
494 {
495 fwrite (output_delimiter_string, sizeof (char),
496 output_delimiter_length, stdout);
497 }
498 print_delimiter = true;
499 }
501 putchar (c);
502 }
503 }
504 }
505 }
507 /* Read from stream STREAM, printing to standard output any selected fields. */
509 static void
510 cut_fields (FILE *stream)
511 {
512 int c;
513 size_t field_idx = 1;
514 bool found_any_selected_field = false;
515 bool buffer_first_field;
517 current_rp = rp;
519 c = getc (stream);
520 if (c == EOF)
521 return;
523 ungetc (c, stream);
524 c = 0;
526 /* To support the semantics of the -s flag, we may have to buffer
527 all of the first field to determine whether it is 'delimited.'
528 But that is unnecessary if all non-delimited lines must be printed
529 and the first field has been selected, or if non-delimited lines
530 must be suppressed and the first field has *not* been selected.
531 That is because a non-delimited line has exactly one field. */
532 buffer_first_field = (suppress_non_delimited ^ !print_kth (1));
534 while (1)
535 {
536 if (field_idx == 1 && buffer_first_field)
537 {
538 ssize_t len;
539 size_t n_bytes;
541 len = getndelim2 (&field_1_buffer, &field_1_bufsize, 0,
542 GETNLINE_NO_LIMIT, delim, '\n', stream);
543 if (len < 0)
544 {
545 free (field_1_buffer);
546 field_1_buffer = NULL;
547 if (ferror (stream) || feof (stream))
548 break;
549 xalloc_die ();
550 }
552 n_bytes = len;
553 assert (n_bytes != 0);
555 c = 0;
557 /* If the first field extends to the end of line (it is not
558 delimited) and we are printing all non-delimited lines,
559 print this one. */
560 if (to_uchar (field_1_buffer[n_bytes - 1]) != delim)
561 {
562 if (suppress_non_delimited)
563 {
564 /* Empty. */
565 }
566 else
567 {
568 fwrite (field_1_buffer, sizeof (char), n_bytes, stdout);
569 /* Make sure the output line is newline terminated. */
570 if (field_1_buffer[n_bytes - 1] != '\n')
571 putchar ('\n');
572 c = '\n';
573 }
574 continue;
575 }
576 if (print_kth (1))
577 {
578 /* Print the field, but not the trailing delimiter. */
579 fwrite (field_1_buffer, sizeof (char), n_bytes - 1, stdout);
581 /* With -d$'\n' don't treat the last '\n' as a delimiter. */
582 if (delim == '\n')
583 {
584 int last_c = getc (stream);
585 if (last_c != EOF)
586 {
587 ungetc (last_c, stream);
588 found_any_selected_field = true;
589 }
590 }
591 else
592 found_any_selected_field = true;
593 }
594 next_item (&field_idx);
595 }
597 int prev_c = c;
599 if (print_kth (field_idx))
600 {
601 if (found_any_selected_field)
602 {
603 fwrite (output_delimiter_string, sizeof (char),
604 output_delimiter_length, stdout);
605 }
606 found_any_selected_field = true;
608 while ((c = getc (stream)) != delim && c != '\n' && c != EOF)
609 {
610 putchar (c);
611 prev_c = c;
612 }
613 }
614 else
615 {
616 while ((c = getc (stream)) != delim && c != '\n' && c != EOF)
617 {
618 prev_c = c;
619 }
620 }
622 /* With -d$'\n' don't treat the last '\n' as a delimiter. */
623 if (delim == '\n' && c == delim)
624 {
625 int last_c = getc (stream);
626 if (last_c != EOF)
627 ungetc (last_c, stream);
628 else
629 c = last_c;
630 }
632 if (c == delim)
633 next_item (&field_idx);
634 else if (c == '\n' || c == EOF)
635 {
636 if (found_any_selected_field
637 || !(suppress_non_delimited && field_idx == 1))
638 {
639 if (c == '\n' || prev_c != '\n' || delim == '\n')
640 putchar ('\n');
641 }
642 if (c == EOF)
643 break;
644 field_idx = 1;
645 current_rp = rp;
646 found_any_selected_field = false;
647 }
648 }
649 }
651 static void
652 cut_stream (FILE *stream)
653 {
654 if (operating_mode == byte_mode)
655 cut_bytes (stream);
656 else
657 cut_fields (stream);
658 }
660 /* Process file FILE to standard output.
661 Return true if successful. */
663 static bool
664 cut_file (char const *file)
665 {
666 FILE *stream;
668 if (STREQ (file, "-"))
669 {
670 have_read_stdin = true;
671 stream = stdin;
672 }
673 else
674 {
675 stream = fopen (file, "r");
676 if (stream == NULL)
677 {
678 error (0, errno, "%s", file);
679 return false;
680 }
681 }
683 fadvise (stream, FADVISE_SEQUENTIAL);
685 cut_stream (stream);
687 if (ferror (stream))
688 {
689 error (0, errno, "%s", file);
690 return false;
691 }
692 if (STREQ (file, "-"))
693 clearerr (stream); /* Also clear EOF. */
694 else if (fclose (stream) == EOF)
695 {
696 error (0, errno, "%s", file);
697 return false;
698 }
699 return true;
700 }
702 int
703 main (int argc, char **argv)
704 {
705 int optc;
706 bool ok;
707 bool delim_specified = false;
708 char *spec_list_string IF_LINT ( = NULL);
710 initialize_main (&argc, &argv);
711 set_program_name (argv[0]);
712 setlocale (LC_ALL, "");
713 bindtextdomain (PACKAGE, LOCALEDIR);
714 textdomain (PACKAGE);
716 atexit (close_stdout);
718 operating_mode = undefined_mode;
720 /* By default, all non-delimited lines are printed. */
721 suppress_non_delimited = false;
723 delim = '\0';
724 have_read_stdin = false;
726 while ((optc = getopt_long (argc, argv, "b:c:d:f:ns", longopts, NULL)) != -1)
727 {
728 switch (optc)
729 {
730 case 'b':
731 case 'c':
732 /* Build the byte list. */
733 if (operating_mode != undefined_mode)
734 FATAL_ERROR (_("only one type of list may be specified"));
735 operating_mode = byte_mode;
736 spec_list_string = optarg;
737 break;
739 case 'f':
740 /* Build the field list. */
741 if (operating_mode != undefined_mode)
742 FATAL_ERROR (_("only one type of list may be specified"));
743 operating_mode = field_mode;
744 spec_list_string = optarg;
745 break;
747 case 'd':
748 /* New delimiter. */
749 /* Interpret -d '' to mean 'use the NUL byte as the delimiter.' */
750 if (optarg[0] != '\0' && optarg[1] != '\0')
751 FATAL_ERROR (_("the delimiter must be a single character"));
752 delim = optarg[0];
753 delim_specified = true;
754 break;
756 case OUTPUT_DELIMITER_OPTION:
757 output_delimiter_specified = true;
758 /* Interpret --output-delimiter='' to mean
759 'use the NUL byte as the delimiter.' */
760 output_delimiter_length = (optarg[0] == '\0'
761 ? 1 : strlen (optarg));
762 output_delimiter_string = xstrdup (optarg);
763 break;
765 case 'n':
766 break;
768 case 's':
769 suppress_non_delimited = true;
770 break;
772 case COMPLEMENT_OPTION:
773 complement = true;
774 break;
776 case_GETOPT_HELP_CHAR;
778 case_GETOPT_VERSION_CHAR (PROGRAM_NAME, AUTHORS);
780 default:
781 usage (EXIT_FAILURE);
782 }
783 }
785 if (operating_mode == undefined_mode)
786 FATAL_ERROR (_("you must specify a list of bytes, characters, or fields"));
788 if (delim_specified && operating_mode != field_mode)
789 FATAL_ERROR (_("an input delimiter may be specified only\
790 when operating on fields"));
792 if (suppress_non_delimited && operating_mode != field_mode)
793 FATAL_ERROR (_("suppressing non-delimited lines makes sense\n\
794 \tonly when operating on fields"));
796 if (! set_fields (spec_list_string))
797 {
798 if (operating_mode == field_mode)
799 FATAL_ERROR (_("missing list of fields"));
800 else
801 FATAL_ERROR (_("missing list of positions"));
802 }
804 if (!delim_specified)
805 delim = '\t';
807 if (output_delimiter_string == NULL)
808 {
809 static char dummy[2];
810 dummy[0] = delim;
811 dummy[1] = '\0';
812 output_delimiter_string = dummy;
813 output_delimiter_length = 1;
814 }
816 if (optind == argc)
817 ok = cut_file ("-");
818 else
819 for (ok = true; optind < argc; optind++)
820 ok &= cut_file (argv[optind]);
823 if (have_read_stdin && fclose (stdin) == EOF)
824 {
825 error (0, errno, "-");
826 ok = false;
827 }
829 return ok ? EXIT_SUCCESS : EXIT_FAILURE;
830 }